"For the Fallen" is a “war poem” written by Laurence Binyon (1869-1943). It was first published in The [London] Times in September 1914. The quoted stanza is most often anthologized and is said to be the first stanza he composed, from which the others sprang in rhythm, content, and mood.
https://en.m.wikipedia.org/wiki/For_the_Fallen
https://allpoetry.com/For-The-Fallen
https://interestingliterature.com/2022/01/they-shall-not-grow-old-poem-meaning/
His poem about the London Blitz, "The Burning of the Leaves", published in The Atlantic, Nov. 1942, regarded by many as his masterpiece.
https://www.theatlantic.com/magazine/archive/1942/11/the-burning-of-the-leaves-five-poems/657324/
https://allpoetry.com/The-Burning-Of-The-Leaves
